diabetes insipidus

Diabetes insipidus is a condition caused by lack of antidiuretic hormone (ADH). This hormone is produced by the pituitary gland (a tiny gland which lies about in the middle of the skull at about the level of the eyes). Antidiuretic hormone regulates the retention of water in the body by the kidneys - more hormone, more water retention. The pituitary secretes this hormone in proportion to the concentration of salts in the bloodstream, to keep the concentration of the bloodstream at the optimal level (the "serum osmolality").

In children, diabetes insipidus is most often caused by destruction of the pituitary by a tumor. Systemic disease such as encephalitis, tuberculosis, serious systemic fungal infections, and leukemia are also occasional causes. There are rare hereditary cases as well. Severe head trauma or brain surgery can cause temporary or even permanent diabetes insipidus.

A child with full blown diabetes insipidus loses water in the urine at a prodigious rate (1 to 3 gallons a day); this water must be replaced by drinking or death would rapidly follow. Truly insatiable thirst is the result. Children with diabetes insipidus drink equally prodigious amounts of water. Deprived of access to normal sources, they will literally drink from the toilet if necessary.

Treatment of diabetes insipidus is by hormone replacement. This has been made infinitely more practical by the availability of synthetically produced ADH, either as a nasal spray or in tablets (these preparations of course are most often prescribed in pediatric medicine for the treatment of bedwetting).